COTTONY SCALE - "Cottony" describes the white cotton-like egg cases which house the young scale insects. Two common cottony scale are cottony taxus scale (Pulvinaria floccifera) and cottony maple scale (Pulvinaria innumerabilis). Cottony taxus scale can be found on camellia, holly, yew, euonymus and maple.  Cottony maple scale is found on maple, elm, hawthorn, dogwood, sycamore, poplar and linden. Heavy infestations cause leaves to turn yellow to light green and may cause stunted growth of the leaves.  The insects appear on the under sides of leaves around cottony masses. To control the pests early in the season use a dormant horticultural oil in early spring.  During the growing season, use horticultural oil or soap.